Discovery and Treatment of Action Potential-Independent Myotonia in Hyperkalemic Periodic Paralysis.

ABSTRACT:

Objective

Hyperkalemic periodic paralysis (hyperKPP) is characterized by attacks of transient weakness. A subset of hyperKPP patients suffers from transient involuntary contraction of muscle (myotonia). The goal of this study was to determine mechanisms causing myotonia in hyperKPP.

Methods

Intracellular electrophysiology, single-fiber Ca²⁺ imaging, and whole muscle contractility studies were performed in a mouse model of hyperKPP.

Results

Myotonia in hyperkPP was caused by both involuntary myogenic action potentials (AP myotonia) lasting less than 5 min and action potential-independent myotonia (non-AP myotonia) lasting over 1 h. Non-AP myotonia was caused by prolonged subthreshold depolarization and elevated intracellular Ca²⁺ in the absence of

SUBMITTER: Dupont C 

PROVIDER: S-EPMC12516254 | biostudies-literature | 2025 Oct

REPOSITORIES: biostudies-literature